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CVE-2026-115889

Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation

CVSS score

9.9

EPSS probability

—

Risk score

1.0

Published

2 h ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

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Vulnerability description

DayBreach AI Explanation

Verified against sources

Critical Overflow Vulnerability in Wasmtime Cranelift Compiler

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

The bit-packing method in the Wasmtime Cranelift compiler backend can silently overflow when compiling sufficiently large or specially crafted Wasm functions, leading to sandbox escapes and type confusion.

Why does it matter?

This critical vulnerability poses a major security risk as it can lead to the bypass of Wasm sandbox protections and generate attacker-controlled effects.

What should be done?

  • Follow vendor advisories
  • Apply updates for affected versions
  • Review compiler configurations
Chain of evidence and sources2 verified claims

Wasmtime Cranelift derleyicisi bit-paketleme mekanizması sessiz taşmalara neden olabilir.

S0 · daybreach-canonicalS1 · cvelist

Bu zafiyet Wasm sandviçinden kaçış ve tür karışıklığı etkileri yaratabilir.

S0 · daybreach-canonicalS1 · cvelist
Show the technical text from the sources

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend. This issue is fixed in versions 36.0.19 and 43.0.0.

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CWE: CWE-197, CWE-843

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-115889 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1bytecodealliancewasmtime View
2crates.iowasmtime View
3crates.iowasmtime View
Total affected vendors: 2|Products: 3

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
9.9CVSS V31CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HNVD
9.9CVSS V3_1CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HCVE CNA
9.9CVSS 3.x—Vector not publishedGitHub Advisory
0.0CVSS 4.0—Vector not publishedGitHub Advisory

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-115889 is associated with the following CWEs:

CWE-197: Common Weakness Enumeration Entry CWE-197CWE-843: Common Weakness Enumeration Entry CWE-843

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-115889 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsLow
UserGerekmiyor

Official Sources and Advisories

https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-897f-g5gm-fmxmvendor-advisoryhttps://github.com/bytecodealliance/wasmtime/pull/12613vendor-advisoryhttps://github.com/bytecodealliance/wasmtime/pull/14818vendor-advisoryhttps://github.com/bytecodealliance/wasmtime/commit/ba8f7d70caa1825b7f64fa75cd9d03f4a438dae0vendor-advisoryhttps://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aavendor-advisoryhttps://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.19vendor-advisoryhttps://github.com/bytecodealliance/wasmtime/releases/tag/v43.0.0vendor-advisoryhttps://rustsec.org/advisories/RUSTSEC-2026-0380.htmlvendor-advisoryhttps://github.com/advisories/GHSA-897f-g5gm-fmxmvendor-advisory

CVSS Vector Radar Chart

9.9 / 10
Attack VectorNetworkComplexityLowPrivilegesLowUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow privileges
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Follow the vendor

B
bytecodealliance logo
bytecodealliance
C
crates.io logo
crates.io

Weakness Type (CWE & CAPEC)

CWE-197 CWE-843

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CVE-2026-115889 · Wasmtime: Bit-packing in Cranelift…